从Aginity工作台中的星期数和年份中获取星期的最后一天

Question

我正在使用Netezza SQL。

我的数据集中有星期数和年份作为组合条目。 例如，“ 2017年第3周”。 我想使用此字段获取一周中最后一天的日期。 在这种情况下，我应该得到“ 2017年1月21日”。

关于如何做的任何想法？

谢谢。

Answer 1

这是一个可能适合您的示例：

SELECT  DATE(year_num || '-01-01') + CAST(((week_num * 7) - 1) || ' DAYS' AS INTERVAL)
  FROM  (SELECT  CAST(TRANSLATE(SUBSTR(dt, 0, INSTR(dt, ', ')), 'Week ', '') AS BYTEINT) AS week_num,
                 CAST(SUBSTR(dt, INSTR(dt, ', ') + 2) AS SMALLINT) AS year_num
           FROM  (SELECT  'Week 3, 2017' AS dt
                   UNION  ALL
                  SELECT  'Week 19, 2015' AS dt
                   UNION  ALL
                  SELECT  'Week 45, 2016' AS dt) _) _

Answer 2

尝试这个。

          select to_date(lpad(trim(substring(data.dt,5,100)),8,'0'),'ww, YYYY') + interval '6 days' as lastDayOfWeek

         from  (SELECT  'Week 3, 2017' AS dt
           UNION  ALL
          SELECT  'Week 19, 2015' AS dt
           UNION  ALL
          SELECT  'Week 45, 2016' AS dt) data